Seismo-lineament analysis of the Malibu Beach quadrangle, Southern California.

The Santa Monica Mountains are a young, structurally active mountain range within southern California. The purpose of this study was to map seismogenic faults within the Malibu Beach quadrangle. Using available earthquake data, I projected fault-plane solutions onto a digital elevation model (DEM). The intersection of each fault-plane solution with the DEM yielded a seismo-lineament whose width reflected the reported confidence interval associated with the earthquake location. Geomorphic lineaments were identified and mapped by illuminating the DEM at a 45 degree elevation from various azimuths. The lineament maps were used to generate hypotheses about the possible location of structures, which were field evaluated. Field work verified the existence of previously unmapped faults along some lineaments. Some faults are approximately coplanar with earthquake fault-plane solutions, and are tentatively considered seismogenic. Focal mechanism solutions and field observations suggest that strain is partitioned between several active faults, including some with pure strike-slip displacements.